ISBN : 978-81-963532-2-3 (E-Book) • Physical DFD - This type of DFD shows how the data flow is actually implemented in the system. It is more specific and close to the implementation. DFD Components DFD can represent Source, destination, storage and flow of data using the following set of components – Fig 10.1: DFD Components • Entities - Entities are source and destination of information data. Entities are represented by rectangles with their respective names. • Process - Activities and action taken on the data are represented by Circle or Roundedged rectangles. • Data Storage - There are two variants of data storage - it can either be represented as a rectangle with absence of both smaller sides or as an open-sided rectangle with only one side missing. • Data Flow - Movement of data is shown by pointed arrows. Data movement is shown from the base of arrow as its source towards head of the arrow as destination. Importance of DFDs in a good software design 44 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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